The overall research goals envisioned for the Population Center are to provide specific answers to various questions in the field of human reproduction. These questions are in the broad areas of a) improving the diagnosis and treatment of human male infertility, b) putting the analysis of human seminal fluid on a more scientific foundation, and c) increasing the variety and safety of human contraceptive techniques. Specifically, the work planned for the coming year is as follows: 1) Study additional infertile men and controls to determine the relationship, if any, between genital tract infection and infertility. This will include the analysis of correlations between microbiologic data and seminal fluid analyses in the above populations as well as in patients with prostatitis, epididymitis and recurrent NGU. 2) Validate the laser light-scattering spectrometer for the purpose of studying sperm flagellation patterns and develop a means of studying sperm morphology through the use of a video signal. 3) Continue to study the interrelationship between hormones and human spermatogenesis. Two hormone combinations will be administered to normal male volunteers to determine their effect on sperm production: testosterone plus FSH, and testosterone plus hCG. 4) Continue and expand the development of statistical methods for the analysis of seminal fluid data and episodic human hormone data.